If he wants to stay at 1080 for another generation (4 years) the a 6300 is enough.
Considering your budget and what you seem to want out of the pc i would say a 270 + 6300 will keep you nicely for 3-4 years. Then you can save up some more and go ballz deep on the next upgrade.
Also for what it's worth Mantle games will be very light on the CPU as you can see from the oxide demo (an 8350 was down clocked to 2 GHz and there was no FPS loss).